As the development of the Light Emitting Diode (LED) technology in recent years, the lighting industry has changed a lot. More and more LEDs have been applied to lighting devices, especially to filament light. However, the LED light can't light-round as the Tungsten wire. The light emitted from LED have strong directivity. At present the LED filament light always light uneven, and it is easy to generate a dark spot at a portion of one end of the bulb shell due to less light. What's more, because of the strong directivity, the LED filament light always light with small angle, which can't meet the lighting requirements.
Therefore, how to design a LED filament light with uniform lighting effect and big lighting angle is the most urgent technical problem to be solved.